Clinical optical mensuration method



Feb. 4, 1936. A. AMES. JR.. E' AL Re- 19,341

CLINICAL OPT-ICAI; HENSURATION METHOD AND INSTRUMENT Original Filed Aug.13, 1929 5 Sheets-Sheet 1 delerw'* WIr/ fw Jr www? fyi- Feb.v 4; 1936. lf A. AMEs',^J,R E'rm.- R'e."l9,84l

CLINICAL OPTICAL MENSURTION METHOD AND INSTRUMENT original Filed Aug.13. 1929', ssheets-sneef 2 fr@ www V Feb A. AMES,I JR.. ET Al. Re 19,341

CLINICAL OPTICAL MENS'URTION METHOD AND INSTRUMENT' "5 Sheets-Sheet 5'original'Filed Aug. 1:5, 1929 7IIIII Feb. 4, 1936. A. AMES, JR.. Er ALRe- 19,841'

CLINICAL PTICAL MNSURATION' METHOD AND INSTRUIENI originali-md Aug. 13,1929 -s sheets-sumarA 4 Feb 4 1936 A AMEs, JR., ETAL Re. 19,841

CLINICAL OPTICAL MENSURATION METHOD AND INSTRUMENT original Filed Aug.13. 1929 s sheets-sheet 5 Ressued Feb. 4, 1936 CLINICAL OPTICALvDIENSURA'ITION LIETHOD AdelbertAmes, Jr., and Gordon H. Gliddon,Hanover,'N. H., assignors to Trustees o! Dartmouth College, Hanover, N.H., a corporation of New Hampshire original'No. 1,944,811. datedJanuary' 39.19.34. serial No. 385,611, August 13, 1929. Applica. tionfor reissuev March 11,` 1935, Serial No.

Thisinvention relates to a methodand apparatus for the clinicaldetermination of and men.

suration of the physiological optical condition oi the human eyes, fordiagnosis and as an aid to the provision of corrective procedure ordevices. l

. Objects of the invention are to provide a method oi and improveddevices for the accurate clinical determination and mensuration oferrors of joint perception oi visible objects by the eyes, or of eacheye in respect to the other, or the normal expected perceptioni toprovide a method and apparatus for the clinical determination andmensuration of horizontal vertical and cyclotorsional phorias and 4otherconditions of stress '15 or imbalance; to provide means for the clinical.detection and measurement oi an associated phenomenon hereinafterreferred to as retinal slip, and to provide means for the clinicalinvestigation and measurement of certain asymmetries of perceptionascribed to differing responses of the retinas to like objects'. Thesedefects, which may also be described as retinal image asymmetry orocular image asymmetry, and means for alleviating them are explainedmore in detail in the copending application of Adelbert Ames, Jr.

and Gordon H., Gliddon, Serial N0. 385,610, led

August 13,1929.

As herein used, the term retina comprises 'the brain elementscorresponding to the retinal elements in the eyes proper an'd thenervous vtracts interconnecting these elements. The image asymmetry dueto a dierence in the optical images formed by the dioptric apparatus ofthe eyes with vor without the aid of dioptric correction means, or tothe anatomical or physiological diierences o! the retinal structurebringing` the dioptric images to consciousness, or to both,

may also be `referred to as differencevof ocular images, that is to saytheactual total visual impression of an eye however obtained.

The apparatus of this invention improves vupon and supplements the`apparatus for clinical opti- Ycal mensuration described and claimedinthe application for patent oi Adelbert-Ames, Jr., Se-

rial No. 272,027,1iied April 23, 1928, and it is understood that inaddition to the'new tests which can be made with the present device, allinvestigations i'or which the older instrument is suited can also beexecuted with the aid oi the apparatus to beA described herein.Investigation and determination oi perception phenomena. including theabove-mentioned diilerent response of the retinas to comparable objects,that is the ocular image diilerence, involves the relation oi l ocultan`images in binocular vision, and their com- 39 claims. V(criss- 2mparison by relative adjustment thereof; is preferably carried out inconnection with apparatus capable of fixing conditions for simultaneousbinocular vision of the patients eyes, and may com-` prise comparison oithe perceptive reaction. to

images of like objects binocularly fused and uri--` like objects vnotiused, with provision for control and mensuration of vergence angles,retinal slip and ocular accommodation at diering distances of therespective objects.' In one aspectl the invention provides targets orobjectholders having devices for' accurate measurement ci relativedistance oi the objects in the field of view, of dimension in respect toeach' other and of position or orientation in a plane at right angles tothe axis oi vision.

The invention will now be described in connection with recommendedspecic forms only oi apparatus representative of` the genus of theinvention and selected for illustration in the ac-` companying drawings,in' which Fig. 1 is a view in elevation of artarget; Fig. 2 `is avertical longitudinal section oi.' the target shown in Fig.` l;

Fig. 3 isa diagram in plan oi onekindoi appurtenant apparatus with whichthe device or Figs. 1 and 2 may be used;

Fig. 4 is a rear elevation of a detail oi the target shown in Figs. land2:

. Fig. 5 is a. iront elevation oran element of one oi the targets;

Fig. 6 is a iront elevation oi the head portion.

oi.' a modiedform o! target;

Fig. 6lv is a detail elevation of a complementary` part of anothertarget made like Fig. 6;

7 is a detail section n line 1-1 of Fig. 6; Fig. 8 is'a detail rightside elevation partly in vertical longitudinal section oi parts shown inF18. -6

target corresponding to Fig. 6;

Fig. 10 is a vertical section partly in elevation of parts shown in Fig.9; and- Figs. l1, l2 and 13 are, respectively, elevations each showing aface view of a complementary pair o! replaceable or'variable objectsadapted to be used one in eachof two of the targets. v

Referring now to Figs. l and 2, each member Fig.'9 is a iront elevationoi another form oi.'

oi a pair oi' targets may comprise a base I having a bottom grooved at 2to fit over a straight slideway 3, 3* or' 3, Figs. 1 and 3, and atubular column l bored to receive a screw l integralwith or attached toan enlarged split annular head 6 lhavl' ing lugs fora clamp screw l.

Column I is mii-led out to a parallel sided aperreilector.

` the heightof screw against a vertical scale I3 on column 4. Collar ilmay be fastened to screw 5 suitably, by a screw I4, for example. 'Ihevertical position of screw 5 and its attachments is controlled by aknurled hand nut I5 taking against the machined upper face of column 4.

VAnnular head 6 may be clamped on the cylindrical hollow barrel I6 of atarget head having a preferably integral annular flange 4I1 peripherallygrooved at Il and concentrically recessed on one face at I9. Barrel I 6may be closed at one end by an extension and head 2I having a concentricnipple 22 in which is mounted a socket 23 for a suitable incandescentlamp 24 lit by current leads 25; the interior oi' the lanternconstituted by the barrel I6 and heads 24 and 2| may be enameled whiteor lined with a white substance or provided with any other suitable Ifit is desired to use a very bright and hot lamp at 24, not usuallynecessary, suitable holes may be provided at 26 for ventilation.

A dinusion screen of thin ground glass or other diffusion material, or acollar screen 28 may be mounted in the frontend of the bore of barrelI6,

against a slip ring 29, but this is not necessary' for the recommendedtypes of light-emitting object discs 21, which maybe of any desired kindof translucent or opaque thin sheet body ca.-

pable of showing drawn, engraved, printed or vmail be discs madeoftranslucent or opaque stii Paper or white pigmented sheet material suchas coated metal, celluloid or a phenolaldehyde condensation product, orany other suitable sheet substance, some having artificial star holeslil and the same or others having dark-line opaque visual objects II ofany desired character, of which preferred forms will presently beexplained. Any form 'of lantern capable of illuminating a bright pointfor an artiiicial'star may be substituted for the barrel II and lamp 24.

'I'he target discs 21 are preferably mounted by cementing or otherwiseon a rotatably adjustable holder, as shown a fiat annulus 40 tting forrotation in the recess I9, and movable 'by either of two knurled-headshoulder screws 4I, -4I, in threaded holes in annulus'4 taking throughconcentric sector slots 42, 42, Figs. 4 and 5, in flange I1,andbindingthebackface'of saidflange. Concentrlc with recess Il andannulus 4l the front surface of nange I1 is graduated in circularmeasure or asI shown, carries a scale 43, which as shown-'in Fig. 5may-be graduated in each direction from at least one quadrant pointthrough a 45 arc. An index mark I5 ,ona'nnulus4lniayberealiasainst'scale4lV Y .l

The target headis preferably provided in addi;- tlmi to one of the ,21;.with a concentrically rotatable object adapted'to be mowed to vanyanguiar position about the center `oi? a disc 215. As shown in Figs. 1and 2 flange I1 may supportfor rotation an internally shouldered ring44,havil18 an exterior' seat for a glass or other transparent disc 45,heldin place by annulus 41suitably fastened 44. Ring 44 may beturned.and

' groove I8. 'l

clamped by a binding 'screw 49 taking into 'Ihe interior face of' disc45 is marked, preferably by pigment-filled engraving, to'constitute anobject, typically the diametrical line 50, 'inline with a similarlyconstructed indexV mark 5I which may have an accompanying Vernier scale52 reading against scale 43. These dispositions are such as to provide atarget in which the mark or marks on the transparent rotatable element46 may be inclined either to the target disc indications behind it or toa visually superposed image of an'- other target in projected concentricrelation Ito it and its target disc, through a measured arc; andsuch asto provide, in the case of two similar targets, for accurate verticaland rotative adjustment for exact optical superposition of the centralaxis and rotation Aabout this axis of -two object targets; and affordingprovision for fused vision of two targets by both eyes, severallylooking at each, when the targets are actually or virtually within thefusional amplitude of an observer whose. eyes are under examination.Additionally, each or either target has'at least two component elementsadapted to be rotated on the same axis independently to an accuratelymeasurable extent. It will be understood that displacement of the disc21 in respect to the zero of` scale 43 may be measured accurately byalignment with the mark 50 -on disc 46,- displacements of which can beread by vernier 52; usually directreading of markv39 against scale 43 issutilcient.

The races of the visual objects carried by the elements of the targetsmay be illuminated for vision by reflected light; for example,` eachbase I may carry for universal adjustment one or more illuminators, hereshown as two small projectorsv 54, 55, each having an` incandescent lamp58 and lens 51, mounted on lugs 58, 59, of base I, for

example by ball-and-pinch-socket linkages 60,'

5I as shown, and having suitable circuit connections 52, 63. In somecases itis desirable to light only Athe central areas within the borderof discs 21, and the projectors 54, 55 may each be arranged to providethis. I f

For certain measurements of disagreement between the eyes of dimensionalperception of objects severally perceived, it is desirable to providearlV object quantitatively variable in dimension A of the glass'disc 46.with a metal bridge 65 having an edg'e 65 on a chord of the ring 44 andhaving a. hole for a shouldered screw 51 held by a flat nut 6l, Fig. 8and having a-head bored and threaded transversely for a micrometer screwel, held against longitudinal movement by shoulders tak?v ing againstfaces of a slotted bearing 10 mounted on the face of a slide 1I slottedat 12 for 51, which holds it against bridge l5, slide 1I also having alongitudinal shoulder fitting against edge 65. On-one face of slide 1I',aiiependms rectangular glass plate 13 is cemented to more with slide 1|parallel with chord. ce in relation f -50 without'change of vergence,accommodationor distance. Usually, it is desirable to measure thetrically to the axis by a distance measured by a scale 1I'L on slide 1Iread against a vernier 1lb mounted on screw 61.

The corresponding object disc oi the complementary targets of thisdevice may comprise an annulus 40 like the annulus 40 above explained,but it is preferred to have the actual objects movable a measurabledistance toward and from the center. For this annulus 4l)n may beprovided with `dovetail slots 40 for rack slides 15', 1'5 each havingvernier scales 15*l to read against a scale 15b on the face of ring 401.Hand pinion shafts I 4|'L corresponding to the screws 4I and extendingthrough the slots 42 have bearings in holes in the annulus 40e, and bythese the slides 15 may be independently adjusted radially.

Ihe disc 21 may be slotted radially at 211, 21e over the slides 15,which may be of the same color and value as the disc 21. Each slidecarries 0bject marks, sho'wn as articial star holes 30e. One of thecomplementary targets with the same slides 15 may, if desired, have onthem at the same distances apart as the holes 3i)n broken lines 16, Fig.6. nally lit.

In order to provide objects for fused vision of! the axis in respect towhich there is no shift of position of the eye axes for determinationsof discordant dimensional perception of one eye relative to the other,and referring now to Figs. 9, l0 and 13, one target may have aheterogeneous central object 'as 34, and the other a central star Vall,on the binocular combination of which objects, adjustments having been4made for phorias as presentlyfexpl'ained, the patient's attention isfixed. Preferably dimensional `percep- In use lone target is notintertion is to be related to the fused-binocular perception of anobject off the central axis, the inquiry by experiment being as todiil'erence in holes in a bearing lug 82 on frame 80 into which groovesstudi-point screws 84 enter.

82, 82* respectively engage internally threaded Y nuts I5, 85| onprojections erected from slides 8,1 having edges 88 bearing on an edge80 of the frame 80 which defines a chord of the ring 44. The slides 81have cemented thereto rectangular glass plates 90 teach of which isprovided with an object, preferably the same kind of object, such as thelines 35 and '36. 'I'he lower ends of the glass plates 90, 91|n may beguided as shown be'-v hind one edge `of the frame 80. The slides B1 eachmay carry an index 88 reading against one of the scales 9i on frame 80to measure displacement from center of the objects on yplates 90, 90e.'Ihe devices of Fig. 6 and of Fig. 9 are rotatable with ring 44 aboutthe center of the target as in thefcase of the device of Fig. 1,v y

Referring now to Fig. 3, and assuming vthe patient's eyes OS and OD tobe placed so that Vtheir axes of rotation horizontally, vertically andby cyclotorsional motions are at o ando respectively, the apparatus,(which may be that described and claimed in the said application of 'TheSCIEWS Adelbert Ames, Jr. Serial No. 272,027, led April 23, 1928 exceptas hereinspecifed) provides optically piane mirrors m, m', respectivelyperpen- `dicular to bisectors .of the angles o m T and o' m' Tl', T andVT being targets as hereinabove described. Slide tracks 3, 3a, a, and3b, a' are respectively movable in a horizontal plane about centers inthat plane as the ends of angular portions aand a coincident with theprojection on that plane of the points o, o'; the mirrorsm and m arefixed to the tracks, and T and T ca n slide on the virtual optical axesby reflection in mirrors m, Jn. verged, parallelv or diverged, vision ofa fused binocular composite o1' T and T is possible within thehorizontal fusional amplitude of the patient, as if vthese targetsoccupied a position T", or to right or left` of that position and weredirectly viewed. In some cases the mirrors m, m' are half-silvered,` anda target at 'I2 maybe emportions of the targets. -Thes'e diaphragms mayhave differing polygonal openings and be used in out-of-focus position,and are useful to exclude Therefore, OD and OS being con-,

the outer portions of` the targets from fusedv binocular vision.

Referring to Figs. l1, 12 or 13, complementaryl L are placed at an angle(measurable in meter angles on scales :c and y, Fig. 3) to correspond toocular convergence at distances '0, T, o. 'I'2 for normal binocularvision of an object at 'I'2 and the eyes are accommodated therefor, thecentral rings of Fig.. 11 will appear as one object. But if the targetface having the stars 30* 30 only is dark, and the lamp 24 is lit, theeyes are disassociated, and the star images will not coincide with thedots 3|, 3|, unless the patient's eye viewing the artificial stars isfree from muscular imbalance (horizontal or vertical phoria). 'A

central single star image will serve for this de- -f' termination, andthe target for the other eye may be at T2. In either case the amount ofangular adjustment of track 3b and of vertical adjustment by hand nut i5of the internally lit target required to bring about coincidencemeasures and compensates for these phorias. s

Conditions may be reversed for the same determination for the other eye.Y

There are'many patients who are still unable.

when axial coincidence of star image and unlike corresponding mark issecured, to bring corresponding star and mark into coincidence becauseone system appears Vto be rotated about the other. This will occurwhether or not there is actual fusion at the center, as Whenthe targetsof Fig.

andior this purpose two targets having linear objects like 32h, 32 onthe disc 46 aiord by readings of mutual or individual rotation of thediscs M and report of limits of fusion or separation a valuablemeasurement. The apparatus described permits these and othermeasurements to be carried out at varying vergences and accommodations,which have significant relation to the comparative ocular function. fAlso oi diagnostic signicance are phenomena which we have named retinalslip. In the case oi' fused vision on the like objects of'such targetsas those of Fig. 11 or Fig. 12 (in which a diametrical line c-f starholes 30* corresponds to the gaps in similarly spaced vertical lines 3l)it has been observed that when the eyes are associated by convergence onand fused vision oi.'

'perceptive' error in this phenomenon, but the devices of Figs. 11 and12 afford suilicient indica` tion of disappearance, direction andmagnitude oi these phenomena by the report of the patient ci what hesees.

There are patientswho, when observingtargets of the kinds hereinmentioned under conditions correcting phorias and the retinal slipphenomena, ii they should have such defects or, ii no such defects canbe found, are nevertheless unable to secure perspective correlation ofthe unlike kinds vci' objects, and in whose eyes the identically spacedobjects on the targets do not activate identically spaced retinalperceptions or identical ocuar images. Refractive ametropia being notpresent or eliminated, the phenomena demonstrate an asymmetry of retinalperceptionor ocular image diil'erence. In the case of the objects ofFig. 11, for example, these persons may note that the star images on onearm or another or throughout their distribution are spaced diilerentlyfrom the corresponding dots. Targets of the kind of Fig. 12 can be usedin di'erent positions to investigate the quantity, sign and orientationof thesepeculiarities.` Local correction, on one side or the other, iorexample, may be found bv changes of the relative positions oi' lines ofvision from the eyes to corresponding objects or corrective lensessimilar to lenses described in copending application 'Serial No. 385,610for use in spectacles to be worn like the conventional eyeglasses. Such'correction may involve overall size diil'erenceswhich are taken carexofby placing a size increasing lens before one eye or a size decreasinglens before the other eye. or, in extreme cases, by placing lenseshaving opposite effects in iront of eyes respectively. Meridional ocularimage dir ferences or retinal asymmetry on a certain meridian arerectified with cylindrical size changing lenses, and defects whichinvolve both over-all and meridional size defects can be corrected by anappropriate lens combination. VThese corrective lenses are placedbetween vthe eyes and the mirrors m, m (Fig. 3) as indicated at a, a',these lenses being supported in suitable holders which may be similar tothose described in the above-mentioned copending application.Quantitative measurements of local displacement may be accurately madeby use oi' the movable objects of the devices oi' Figs. 6 and 9. Theprocedure is to displace the slides of these devices to bring aboutlocal coincidence of the unlike ob- Y jects,` and measure thedisplacements scales of the apparatus.

In the kind oi target device shown in Fig. 13 for which see the devicesof Figs. 9 and 10, ob jects capable of being fused are provided at 35,35u on the movable slides for variation of their onthe distanceseverally from the axial star 30 and gap In the device of Fig. 6 motionof in line Il, the fused object could be utilized to determineasymmetry, but this involves a sluit oi the direction of attention. Incase of the device oi' Fig. 9, attention remains ixed on the 'star andgapped line device, and the fused gure is displaced to bring aboutcoincidence and investi-` functions structures and performances undervariable conditions o! vergence and accommodation as will be apparent tothose skilled in optical diagnosis.

We claim: i' 1. Apparatus for the clinical determination of errors ofjoint ocular perception having therein in combination, apparatuspermitting and inducing joint vision oi Atwo or more objects, one byeach eye, and targets having thereonl like objects for visual fusion andunlike objects for appaient projection on each other specially arrangedin reference to each other, whereby j udgment can be made of therelative displacement of the dissimilar objects. v

2. Apparatus for the clinical determination of errors of joint ocularperception having therein in combination', apparatus permitting andinducing joint vision of, two or more objects, one by eachV eye, andtargets having thereon like objects for visual fusion and unlike objectsfor apparent projection on each other, and means permitting one kind ofobject to be moved in relation to the other kind.

3. Apparatus for the clinical determination of errors of joint ocularperception having therein in combination with apparatus inducing jointvision oi.' two or more objects. one by eachy eye, targets affordinglike objects for visual fusion and unlike objects for apparentprojection on each other, means permitting one kind of object to bemoved -in relation to the other kind, and means for measuring deviationsot the appearance of one kind of object from the other kind.

4. Apparatus for the clinical determination of errors oi joint ocularperception having therein in combination, apparatus permitting andinducing joint vision oi.' two or more objects, one by each eye, andtargets having vthereon mutually related spaced series of like objectsfor visual fusion and similarly spaced unlike objects for apparentprojection on each other, and means' permitting one kind of object vtobe movedin relation to the other kind.

5. Apparatus for the clinical determination of errors of joint ocularperception having therein in combination with apparatus inducing tovjoint. vision of two or morev objects, one by each eye.

targets aording like objects for visual fusion and unlike objects forapparent projection on each other and means permittinghorizontal,cycloangular, distance, and vertical adjustment of said targetsseverally.

6. Apparatus for the clinical determination of errors of jointocular'perception-having therein in combination with apparatus forinducing joint vision of two or more objects, one by each eye, targetshaving thereon like objects for fusion and unlike objects respectivelyon each target in the same spacial relation, in combination with s meansi'or moving the objects of one kind about an axis common to thebinocular appearance of'y both kinds of objects. i

7. Apparatus for the clinical determination of errors 'oi joint ocularperception having therein in combination with apparatus for causing.joint vision oi two or more objects, one by each eye, targetscharacterized by objects respectively alike for binocular fusion andunlike but spacially similar, the respectiveobjects having elementsseverally rotatable about the virtual axes of the respective eyes inrelation to each target. 8. Apparatus for the clinical 'determination oferrors of joint ocular perception having therein in combination withapparatus for causing joint vision of two or more objects, one by eacheye at variable vergences and variable virtual distances, targetscharacterized by objects respectively alike for binocular fusion andunlike but spacially simi-y lar, the respective objects being severallyrotatable about the virtual axes of the respective eyes in relation toeach target.

' 9. Apparatus for the clinical determination of errors of joint ocularperception having therein in combination with apparatus for causingjoint vision'of two or more objects, one by eacheye,

targets having provision forlvertical adjustment of an axis of rotation,and severally comprising a transparent member carrying an object formotion in respect to said axis, and a member having object markingsadapted to be rotated about said 1 axis through substantial angles.

10. Apparatus for the clinical determination of errors of joint ocularperception having therein in combination with apparatus for causingjoint vision of two or more objects, `one `by each eye, targets havingprovision for vertical adjustment ot an axis of rotation, and severallycomprising a transparent member carrying an object for motion in'respectto said axis and a member having object markings adapted to be rotatedabout said axis through substantial angles, and means permittinghorizontal angular adjustment oi' the position oi' said targets inrespect to the axis oi horizontal rotation oi' each eye.

1l. In a target device for optical mensuration `apparatus comprising' aplurality oi targets each comprising an object i-ield displaying visualobjects, in combination, standards bearing complementar-y visualobjects, at least one of said targets comprising a lantern for theillumination of an articial star hole in the object eld oi thetarget,vand at least one o t said targets comprising a sheet bearing amark and means for turning said sheet through a measured angle about anaxis perpendicular to said sheet and sai object eld.

12.4.In a target device for optical mensuration apparatus comprising aplurality oi targets each comprising an object ileld displaying visualob-A jects, in combination, standards bearing complementary visualobjects, at least one ot said tar-y -gets comprising a lantern for theillumination of an artificial star hole in the object ileld of thetarget, saidtargets each comprising a sheet bearing a mark and means forturning said sheet through a measured angle about an axis perpenfdicular tosaid sheet and object field, and at least one targetcomprising means for adjusting an object upon it toward and away fromsaid axis.

i3. In a target device for optical mensuration apparatus comprising aplurality of targets, in combination, standards each bearing one ofcomplementary visual objects, at least one of said targets comprisingthe object eld displaying visual objects, a lantern for the illuminationof an articial star holeI vin the object ileld of the target, saidtargets each comprising asheet bearing a mark and means for turningsaidsheet through a measured angle about an axis perpendicular to said sheetand said object field, and at least one target comprising meansioradjusting, its objecteld device having an articial star hole in ittoward and away from said axis.

14. In a target device for optical mensuration apparatus, thecombination of a head having a ange and a recess, an annular holder i'oran object-sheet rotatable in said recess, a ring mounted for rotation onsaid flange, and a cooperating object mark carried by said ring forconcentric rotation.

15. Target device for clinical optical mensuration apparatus havingtherein a scale for measuring rotation about a center, an annulusadapted to bear a disk object for rotation about said center, and atransparent sheet mounted for rotation about said center, said annulus'and sheet having indices related to said scale; and means forilluminating a hole in said disk object.

16. Clinical optical apparatus having therein a target having objectmarkings including an arti-` iicial star hole in the target, means forilluminating the hole, and a complementary object mounted for lateralmotion in respect to said 17. Clinical optical apparatus having thereinatarget having object markings including an articial star hole in thetarget, means for illuminating the hole, and two objects mounted forlateral motion in `respect to said hole and each other. r

18. `Apparatus vfor the clinical determination of errors oi' jointocular perception having therein in combination with apparatus inducingjoint vision of two or more objects, one by each eye, targets aordinglike objects for visual fusion and unlike objects for apparentprojection on each other, means permitting horizontal, cycloangular,distance, and vertical adjustment oi said targets severally, meanspermitting one kind' ot object to be movedin relation to a target andthe projected appearance oi objects of the other kind, and means formeasuring deviations oi the appearance of one kind oir object from theother kind;

19. Apparatus for the' clinical determination of errors o1' joint ocularperception having therein in combination with apparatus inducing tojoint visual perception oi' images severally formed in each eye of apatient of two or more objects, targets having parts constituting likeobjects for visual fusion by binocular vision andunlike objects forapparent projection on each other by binocular vision, and means formounting said targets for horizontal angular adjustment in relation toeach other.

20. Apparatus for the clinical determination of errors of joint ocularperception having therein in combination with apparatus inducing tojoint targets having parts constituting like objects for v visual fusionby binocular vision and unlike objects for apparent projection on eachother by binocular vision, and means for mounting said* targets forseveral adjustment vertically through known distances in relation to theplane of the binocular axes. i

22. Apparatus for the clinical determination of errors of joint ocularperception having therein in combination with apparatus inducing tojoint visual perception of images severally formed in each eye' of apatient of two or more objects, targets having .parts constituting likeobjects for visual fusion by binocular vision and unlike objects forapparent projection on' each other by binocular vision, and means formounting said targets for several adjustment rotatively about an axisnormal to their faces for cycloangular mensuration.

23. Apparatus for the clinical determination of errors of joint ocularperception having therein in'combination with apparatus inducing tojoint visual perception of images severally formed in each eye of apatient of two or more objects,

V targets having parts constituting like objects for visual fusion lbybinocular vision and unlike objects for apparent projection on eachother by binocular vision, and means for mounting said.

' of one of the objects during simultaneous several vision of therespective eyes, and measuring the angular magnitude of the distortionof the' object for one eye in respect to the other eye required toobtain harmonious and symmetrical fused vision.

25. Apparatus for testing a pair of eyes com'- prising means forpresenting to each eye the appearance of a fusion object, means forpresenting to oneeye the appearance of a test object of one characterplaced on one side of said fusion object,y and means for presenting tothe other eye the appearance of a test object of different charactersimilarly placed in relation to said fusion object.l

,26. Apparatus according to claim 25, further characterized in that aplurality of test objects are placed symmetrically with respect to thefusion object.

27. Apparatus of the character referred to'comprising fusion means forcausing a pair of eyes to converge at a predetermined distance, meansfor presenting to one of said eyes the appearance of test objects of onecharacter denitely placed with respect to said fusion means, and meansfor concomitantly presenting to the other of said eyes 4the appearanceof test objects of a diiferent characier similarly placed with respectto said fusion means.

28. Apparatus for the testing of a pair of eyes comprising means forforming on the retina of each eye like images adapted for binocularfusion, and mea-ns similarly disposed relative to said first means forforming on the several retinas unlike images.

29. Apparatus accordingto claim 28 further comprising means for changingthe apparent separation in one eye relative to the.' other of the imageformed by said second means.

30. 'I'he method of testing the human eye for variance in the sizeimpressions of the ocular images of the two eyes comprising theformation of retinal images which are in part like and in part'unlike inthe respective eyes, changing the relative positions of the like andunlike parts to cause the image in one eye to be similar in extent tothat in the other eye, and measuring said change.

31. The methodaccording to claim 30 further characterized in that theeyes are, tested for meridional size variances by measuring the changenecessary to make the radio ofdimensions on two different meridians ofthe image in one eye similar to the corresponding ratio of the image inthe 32. The method of testing the human eyes for diiferences in sizeimpressions thereof, comprising placing a chart in the line of vision ofeach eye, each chart having a. marking thereon fusible with the otherand each chart having a marking thereon not fusible with the other,fusing the fusible markings with each other and measuring the apparentseparation oi.' the non-fusible markings to determine the variance insize of images. 33. The method of testing a pair of eyes which comprisespresenting to said eyes like semblances of an object and to each eye theform of a test object unlike the form presented to the other eye butsimilarly located with respect to each semblance, causing the eyes tofuse said semblances, and evaluating ocular defects by vobserving theapparent location of said unlike forms in blnocular vision determined bysaid fusion.

34. A device of the character described comprising visual objects havinglike objects thereon which may be fused and unlike objects thereon whichcannot be fused, one visual object being positioned at a given distancefrom each eye, means for superposition of the ocular images o! saidvisual objects with each other, means for displacing the objects untilthe unlikeobjects assume a denite relation with each other, and means tomeasure said displacement to obtain the extent of phorias present.

35. A device of. the character described, comprising test means havingfusible means thereon and non-fusible means given distance ir'om placingYthe image of the non-fusible means of one eye relative to thecorresponding image of the ,other eye, to place the non-fusible imagesin prefrom the eyes, to obtain Acating dimensional lrelative'size oi4said images thereon positioned at a each eye, means forA disdeterminedrelation with each other, and means for measuring the extent of saiddisplacement.

36. Apparatus for testing binocular vision for diiierence of the.ocularimages of. the two eyes, comprising test target means withelements indiproperties `thereof for forming in the respective eyesimages whose dimensions may-be compared, means for relating theconscious appearances of the corresponding ocular images of said targetmeans for comparison thereoi.' in vbinocular vision, means for lchangingthe by adjusting the position of said elements until they assume apredetermined location in superposed appearance, and means fordeterminingthe amount of said adjustment'.

' 3'1.- Apparatus for testing binocular'vision for difference of theocular images of the respective eyes, comprising a test object meansbefore each eye inducing judgment of at least one dimension, means forrelating conscious appearances oi the ocular images oi said test objectmeans yfor comparison thereof., means for .adjusting the relativedimensions of said test object means as perceived through the respectiveeyes, while substantially maintaining the distance oi the respectiveimages a dimensional relation stantially of said ocular images, andmeans for measuringy the amount oi said adjustment.

38. The method of testing binocular vision i'or difference o! the ocularimages oi the two eyes, comprising the formation in the respective eyesof images of test target means which have elements indicatingdimensional properties of said target means, and whose relativepositions may be compared, superposing the conscious appearances of thecorresponding ocular images ci said target means for comparison thereofin binocular vision, changing the relative size of said images byadjusting the position of said, elements until they assume apredetermined location in superi posed appearance, and oi' saidadjustment. 39. In the art of determining the amount son which comprisespresenting to each eye of the person a test object means with elementsfor dimensional comparison relating the conscious apmeans for comparisonthereof, adjusting the relative dimensions of. said test object means asappearing through the respective eyes while submaintaining the distanceof the re` spective images from the eyes, to obtain a dimensionalrelation of said ocular images, and measuring said adjustment.v 4

ADELSERT AMES, Jn. GoaDoN H. GLmDoN.

testing binocular vision the n method of correlating the ocular imagesof a per-

